condition mean min max ZT0-3 8.715946 8.715946 8.715946 ZT4-7 10.6178045 10.6178045 10.6178045 ZT8-11 9.552705 9.552705 9.552705 ZT12-15 8.5068965 8.5068965 8.5068965 ZT16-19 8.6889015 8.6889015 8.6889015 ZT20-23 9.135113 9.135113 9.135113